Still contemplating the Super Twin vs Three 10…
I've seen a number of posts about the voicing of the 10" cabs being so easy to get a great tone while the 12" cabs take more knob turning to get there. I think my GK NeoIV 212 with its punchy response and strong even mids is similar to the Super Twin and I always scoop the upper mids a touch, bump the bass, and add some compression to fatten it up and get my sound. This sounds like the Three10 starting point without any adjustments, which wouldn't be a bad thing. I'm probably not alone in having FOH support but expecting my stage rig to keep up with a hard hitting drummer. The GK 212 rated max SPL is 129dB/1m at full power of 800 watts rms, which provides plenty of headroom for any live situation I'd encounter. The Super Twin has a bit more ultimate volume which I probably wouldn't fully use. The Three10 has a rated max SPL of 128dB/1m at full power which should still be enough to meet this requirement. A P-bass through a Mesa D800+ and Three10 sounds like it would be a sweet rig for rock, blues, and country.